phenylalanine transport

Definition

Target type: biologicalprocess

The directed movement of phenylalanine, 2-amino-3-phenylpropanoic acid, into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. [GOC:ai]

Phenylalanine transport is a crucial biological process that involves the movement of the amino acid phenylalanine across cell membranes. This process is essential for various physiological functions, including protein synthesis, neurotransmitter production, and energy metabolism.

The transport of phenylalanine across cell membranes is facilitated by specific membrane proteins known as phenylalanine transporters. These transporters exhibit high selectivity for phenylalanine and are responsible for the efficient uptake and release of this amino acid in various tissues.

Phenylalanine transport mechanisms can be broadly classified into two main categories: active transport and passive transport. Active transport requires energy to move phenylalanine against its concentration gradient, from an area of low concentration to an area of high concentration. This process is typically driven by ATP hydrolysis or by coupling the movement of phenylalanine to the movement of another molecule down its concentration gradient.

Passive transport, on the other hand, does not require energy and occurs down the concentration gradient, from an area of high concentration to an area of low concentration. This type of transport can be further subdivided into simple diffusion, facilitated diffusion, and osmosis. Simple diffusion involves the movement of phenylalanine across the cell membrane without the assistance of any membrane proteins. Facilitated diffusion, however, requires the presence of specific membrane proteins to facilitate the movement of phenylalanine.

In the context of phenylalanine transport, the most common mechanisms include:

- **System L:** This is a sodium-independent transporter that exhibits a high affinity for phenylalanine and other large neutral amino acids. It is widely expressed in various tissues and is responsible for the uptake of phenylalanine from the bloodstream into cells.

- **System A:** This transporter is sodium-dependent and exhibits a lower affinity for phenylalanine compared to system L. It is primarily responsible for the uptake of small neutral amino acids, including alanine, serine, and glycine, but also transports phenylalanine to a lesser extent.

- **System y+L:** This transporter is a sodium-dependent system that transports both phenylalanine and tyrosine. It plays a significant role in the uptake of these amino acids in the brain and other tissues.

- **System B(0,+):** This transporter is a sodium-dependent system that primarily transports basic amino acids, but it also transports phenylalanine. It is expressed in the small intestine and plays a role in the absorption of phenylalanine from the diet.

The specific mechanisms of phenylalanine transport vary depending on the cell type, tissue, and physiological conditions. These transport systems are tightly regulated to ensure the appropriate levels of phenylalanine in different cellular compartments. Dysregulation of phenylalanine transport can lead to various health problems, including phenylketonuria (PKU), a genetic disorder that impairs the metabolism of phenylalanine.

The transport of phenylalanine is a complex process that is essential for maintaining cellular homeostasis and overall health. The intricate interplay of different transport systems and regulatory mechanisms ensures the efficient and regulated movement of this amino acid across cell membranes.'
"

Proteins (1)

Compounds (19)